Oil Spill Puts Pelicans At Risk

Removed from the endangered species list just last year, brown pelicans take a hit in the Gulf of Mexico

07-16-2010
//
Laura Tangley

For many people, the most enduring—and disturbing—memories of this year’s Gulf of Mexico disaster are likely to be the images of oil-soaked seabirds splashed across news media almost daily. And of these, the most upsetting of all often show brown pelicans, those huge, elegant and tremendously popular birds that have become icons for the Gulf Coast.

As of mid-July, the brown pelican is the bird species hit hardest by the oil spill: 58 percent of all dead or injured birds collected to date have been pelicans, according to U.S. Fish and Wildlife Service (FWS) statistics. That worries many conservationists. A rare endangered species success story, the bird was removed from the federal endangered species list only last year. “It’s a species we’re keeping a close eye on,” says biologist Kelly Hornaday of the FWS endangered species program.

The timing of the spill could not have been worse: Pelicans, which nest colonially on offshore barrier islands, were at the start of their annual nesting season when the oil rig exploded in April. According to Hornaday, between 25,000 and 33,000 pairs of pelicans breed on islands off the U.S. Gulf Coast; Louisiana alone hosts between 8,000 and 16,000 pairs, depending on the year. “The majority of the nesting islands getting hit by oil are in Louisiana,” she says. On July 14, biologists from the Cornell Lab of Ornithology reported finding at least 300 oiled pelicans on Raccoon Island—a major rookery—alone.

Most oiled pelicans and other birds are transported to facilities operated by the International Bird Rescue Research Center, where workers evaluate the condition of each animal, then try to clean those they believe can be saved.

RARE BIRD

The brown pelican is unusual among the world’s eight pelican species. Along with the Peruvian pelican—a newly recocognized species once considered the same as the brown pelican—it is the only pelican that lives strictly in coastal habitats, never venturing more than about 20 miles inland or out to sea.

Brown pelicans feed on mid-sized fish they capture by diving headfirst into the water. The birds have excellent eyesight and can spot prey from as high as 60 feet above the water.

After nabbing their catch, pelicans scoop or dip the fish into their pouches, rise to the water’s surface, tilt their bills forward to drain the water, then toss their heads up and back to swallow.

It turns out to be true that a pelican’s “beak can hold more than its belly can:” The bird’s pouch can accommodate about three gallons while its stomach holds only about one.

UNUSUALLY VULNERABLE

Unlike most birds, which keep their eggs warm with the skin of their breasts, pelicans incubate eggs with their feet, holding them under webs that stretch from the front toes to the hind toe.

This unusual incubation method, along with their seafood diet, made pelicans particularly vulnerable to the pesticide DDT, which the birds picked up from contaminated fish. Because a metabolite of DDT—DDE—causes the eggshells of birds to thin, pelican parents accidentally cracked their eggs while attempting to incubate them.

DDT and other pesticides, combined with the effects of shooting the birds for feathers during the early 20th Century, led to pelican population crashes by the late 1950s. Pelicansdisappeared completely from the Pelican State of Louisiana.

REMARKABLE RECOVERY

In 1970, FWS listed the brown pelican as endangered throughout its range (three years before passage of the Endangered Species Act of 1973). A 1972 ban on DDT—along with transplanting thousands of chicks from Florida to Louisiana—led to remarkable population recoveries.

In 1985, Atlantic coast populations of the bird were removed from the endangered species list. In November 2009 the species was removed from the endangered species list entirely. “They’ve been doing very well,” says Hornaday. “Annual surveys by our state partners show either stable or increasing numbers with good nesting success.”

OIL SPILL THREAT

The oil spill may change that. The brown pelican's nesting season is just now beginning to wind down. It should end in a few weeks. And as of Friday, July 16, BP has finally stopped the flow of oil from the well—at least temporarily.

“But there are still millions of gallons of oil floating around out there,” notes Mike Parr, a vice president of the American Bird Conservancy who had just returned from a six-day visit to the gulf. “After the breeding season, pelicans start moving around a lot more, and from what we observed, the boom they’re using to keep oil out of critical areas is hopeless. It doesn’t stand up to even moderate weather.”

Meanwhile, the region is about to enter peak hurricane season.

A RESILIENT BIRD

Might the Pelican State once again lose its pelicans?

Hornaday is cautiously optimistic. “The species may take a hit for a few years,” she says. But as its history in Louisiana shows, “this is a pretty resilient bird.” Brown pelicans evolved to cope with challenges such as hurricanes and periodic crashes in prey caused by El Nino, she says. “The birds are adapted to boom and bust kinds of cycles.”